The invention relates to an accelerator pedal unit comprising an accelerator pedal, an actuator and a control shaft via which the actuator can transmit a restoring torque to the accelerator pedal.
An accelerator pedal unit is already known from the German patent publication DE 10 2009 021 585 A1, comprising an accelerator pedal, an actuator and a control shaft, by means of which a restoring torque can be transmitted to the accelerator pedal. The accelerator pedal unit can generate an additional restoring force which acts on the accelerator pedal, for example in order to regulate or limit the speed of a vehicle or to function as a warning device in the event of speeding. Disadvantageously, the actuator and the accelerator pedal are rigidly coupled to each other. As a result, brief losses of torque of the actuator, for example losses of torque of a brushed DC electric motor (torque ripple), are transmitted to the accelerator pedal with no change in their relative magnitude and are noticeable to the driver in a disruptive manner. A further disadvantage is that the additional restoring force generated by the actuator is subject to uncontrollable fluctuations due to different effects. Firstly, an undesirable increase in the restoring force can occur due to inertia forces as a result of coupled co-movement of the actuator during a quick actuation of the accelerator pedal. Secondly, the mechanical gearing mechanism path is afflicted with friction, so that the force actually transmitted to the accelerator pedal is dependent on temperature. Moreover, the relationship between the generated engine torque and the current applied to the actuator is subject to unpredictable fluctuations which are dependent on temperature and material and component tolerances.